1. Field of the Invention
The present invention is directed to a method for protecting a device against operation with unallowed consumables, and is also directed to an arrangement for the implementation of the method. The invention can be employed for replenishing consumables in a postage meter machine such as, for example, ink cartridges for ink jet printing units or thermal transfer inking ribbon cassettes or rotary printing drums.
2. Description of the Prior Art
Postage meter machines have been known since the 1920's and are still being constantly perfected. The printing principle has changed from original, purely mechanical solutions with printing drums to electronic solutions with thermal transfer or ink jet printing head. Beginning in the 1970's, microprocessors and electronic credit memories were utilized in the increasingly electronic controllers. A standard payment principle, “pay before”, is based on a monetary sum, referred to as the credit amount, being debited from a customer account and administered in the postage meter machine. At every franking, this credit amount is reduced by the franked amount printed on the postal matter. The postage meter machine can be reloaded with a credit amount. At the same time, specific security measures have been developed that are intended to prevent or detect an unauthorized manipulation to the detriment of the manufacturer or the user or the mail carrier. The postage meter machine also uses (consumes) printing ink and the parts belonging to the printing technology wear, so that it is in the interest of the user and of the mail carrier to employ qualitatively high-grade, authorized material of the manufacturer. If, however, so-called pirate products are used, this influences the service life and printing quality of the machine. It is sometimes appropriate, however, for an original product to be recycled by the manufacturer. For example, authorized ink could be refilled into an original cassette for a printing device. Heretofore, however, it has not been possible to completely preclude opportunities for manipulation.
German PS 196 13 944 discloses an ink cassette with two approximately identically constructed ink reservoirs that is suitable for the JetMail® type of postage meter machine. One ink reservoir serves for disposal of ink collected during priming. The other ink reservoir serves for ink supply and in fact has an end of ink detection with two electrodes, but no protection against refilling with an ink not authorized by the manufacturer.
An end of ink detection with electrodes is known from German OS 27 28 283. Two electrodes for a comparative measurement and a separate electrode for a conductivity measurement for signalling the end of ink are introduced into the base of the ink reservoir. The transfer impedance between these electrodes is measured with an electronic circuit and is interpreted. The electrodes are arranged in troughs that are formed in the reservoir base. A pre-condition for the use of such an end of ink recognition is the employment of an electrically conductive ink. Protection against refilling with an ink other than the original ink is not possible.
Sensors for detecting the end of ink already supply the JetMail® system with an end signal—as a safety margin—when a maximum of 200 frankings are still possible in order to avoid an incompletely printed franking imprint, that has already been debited, due to lack of ink. Priming is not possible, however, because the end signal is usually emitted too late to re-order an ink tank.
Cassette-shaped containers with ink fluid, inking ribbon or toner are disclosed in U.S. Pat. No. 5,365,312, which have an integrated circuit chip with an electronic memory for a code identifying the reservoir, for an expiration date and other data, as well as with a counter in order to identify the consumption during printing by counting the individual print pulses. These rules correspond to the drops of ink that are printed out. The integrated circuit stores the current filling status and this can be read out and displayed by the printer controller. Since a reprogramming of the chip and a refilling of the container are not possible, the manufacturer cannot recycle the container.
German PS 196 13 945 discloses a device for preventing re-employment a container for the ink supply of an ink print head. An ink connecting line from the ink print head is docked to the container with a hollow needle via a rubber-elastic closure. One cover mechanism is irreversibly triggered by the hollow needle when the container is pulled off. A refilled ink reservoir can no longer be docked. Unfortunately, this solution also prevents the re-employment of containers filled with original ink. The used ink tanks only can be returned to the dealer or the manufacturer's service department for proper disposal. It is a disadvantage when even a recycled consumable offered by the manufacturer cannot be re-employed. The use of exactly copied pirated ink reservoirs, unfortunately, can not be avoided with this known arrangement. A distinction between original consumable and unauthorized copies thereof is required for that purpose. A consumable that was not checked by the manufacturer or approved by the manufacturer represents a risk to the legibility of the franking imprint. The franking imprint must be capable of being read visually and by machine by the postal authorities in order to be able to verify the payment of postage. Together with other components of the postage meter machine, the consumables employed must therefore be approved by the postal authorities.
European Application 730 974 discloses a solution specifically for thermal transfer inking ribbons. Markings (for example, a bar code at the start of the inking ribbon) are impressed on the inking ribbon by the manufacturer. A detection of this marking (for example, with an optical scanner) is automatically carried out after the insertion of the inking ribbon into the postage meter machine. The data content of the marking is communicated to the control unit of the postage meter machine and is compared to pre-stored reference codes. These reference codes have been non-volatilely stored in the postage meter machine at the manufacturer. In order to counter revelation of the codes, these codes are regenerated at certain time intervals, and can be rolled into the postage meter machine by remote data transmission from a data center of the manufacturer. Every code supplied by the data center also has a time limit, which prevents unauthorized use after the expiration of the predetermined time period. Counting the imprints is also known.
A disadvantage of the above method is the lack of synchronization between the output of the new codes for the consumables and the storing of the corresponding reference codes in the postage meter machine, and the unpredictable point in time of the purchase and installation of the consumables into the postage meter machine. Time overlaps thus necessarily occur, whereby consumables with old codes do not interact with the new reference codes stored in the postage meter machine. If more than one of the codes is declared valid in these transition times, the risk also increases that codes that have become known can be combined with unauthorized consumables without detection.
Another disadvantage is the lack of information for the manufacturer that a specific customer is attempting to employ unauthorized consumables. This information is acquired only by the postage meter machine, which then can react only in a pre-programmed way, for instance by refusing to frank. A flexible reaction to the customer, for example personal telephone contact on the part of the manufacturer combined with a limited-time permission to use the unauthorized material, is thus not possible.
German 198 38 913 discloses a method for originality testing of a product such as, for example, medications, foods and treats or electronics and software products that delivers a message to the manufacturer as to whether a specific customer is using an authorized or unauthorized product. The latter, however, can neither be rendered more difficult nor prevented. Consequently, a device can be operated with unauthorized consumables without legal consequences and disadvantages, particularly when the manufacturer is not necessarily informed thereof, and thus cannot immediately prevent a potential loss of quality.
Indicating an impending change of consumable via display is disclosed in German OS 195 49 376 wherein sensors are used for determining the remaining amount of inking ribbon on inking ribbon cassettes for a thermal transfer printer or to count the number of imprints with the controller of the thermal transfer printer.
Counting the imprints in piezo ink jet print heads cannot provide any information about the quantity of ink remaining in the ink tank because, given a low through medium number of frankings per day, the consumption of ink due to cleaning predominates, thereby reducing the number of possible imprints per ink tank fill. In piezo ink jet print heads, a large part of the ink is used in priming and cannot be resupplied to the head. It is also known to resupply the portion of the ink used during priming to the head. For dependable ink supply, it is therefore important to recognize the end of ink and signal this in time. Given a premature replacement or insertion of a refilled but not completely full ink tank, however, the remaining quantity of ink cannot be exactly determined. Whether a replacement has occurred in the interim thus cannot be determined in a simple manner.